linux-kernel - Re: [PATCH] perf top: Display the LBR stats in callchain entry

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Message-ID: <20181105131027.GC11147@kernel.org>
Date:   Mon, 5 Nov 2018 10:10:27 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     "Jin, Yao" <yao.jin@...ux.intel.com>
Cc:     jolsa@...nel.org, peterz@...radead.org, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com, Linux-kernel@...r.kernel.org,
        ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH] perf top: Display the LBR stats in callchain entry

Em Mon, Nov 05, 2018 at 08:31:59AM +0800, Jin, Yao escreveu:
> Hi,
> 
> Any comments for this patch?

I'll check it today, I'm just a bit behind while preparing for plumbers,
I'll get to all the patches :-)

- Arnaldo
 
> Thanks
> Jin Yao
> 
> On 10/31/2018 7:06 PM, Jin Yao wrote:
> > Perf report has supported the displaying of LBR stats
> > (such as cycles, predicted%) in callchain entry.
> > 
> > For example,
> > perf report --branch-history --stdio
> > 
> > --1.01%--intel_idle mwait.h:29
> >            intel_idle cpufeature.h:164 (cycles:5)
> >            intel_idle cpufeature.h:164 (predicted:76.4%)
> >            intel_idle mwait.h:102 (cycles:41)
> >            intel_idle current.h:15
> > 
> > While perf top has not supported that.
> > 
> > For example,
> > perf top -a -b --call-graph branch
> > 
> > -   13.86%     0.23%  [kernel]		[k] __x86_indirect_thunk_rax
> >     - 13.65% __x86_indirect_thunk_rax
> >        + 1.69% do_syscall_64
> >        + 1.68% do_select
> >        + 1.41% ktime_get
> >        + 0.70% __schedule
> >        + 0.62% do_sys_poll
> >          0.58% __x86_indirect_thunk_rax
> > 
> > Actually it's very easy to enable this feature in perf top.
> > 
> > With this patch, the result is:
> > 
> > perf top -a -b --call-graph branch
> > 
> > -   13.58%     0.00%  [kernel]		[k] __x86_indirect_thunk_rax
> >     - 13.57% __x86_indirect_thunk_rax (predicted:93.9%)
> >        + 1.78% do_select (cycles:2)
> >        + 1.68% perf_pmu_disable.part.99 (cycles:1)
> >        + 1.45% ___sys_recvmsg (cycles:25)
> >        + 0.81% unix_stream_sendmsg (cycles:18)
> >        + 0.80% ktime_get (cycles:400)
> >          0.58% pick_next_task_fair (cycles:47)
> >        + 0.56% i915_request_retire (cycles:2)
> >        + 0.52% do_sys_poll (cycles:4)
> > 
> > Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
> > ---
> >   tools/perf/builtin-top.c | 3 +++
> >   1 file changed, 3 insertions(+)
> > 
> > diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> > index d21d875..7691b21 100644
> > --- a/tools/perf/builtin-top.c
> > +++ b/tools/perf/builtin-top.c
> > @@ -1420,6 +1420,9 @@ int cmd_top(int argc, const char **argv)
> >   		}
> >   	}
> > +	if (opts->branch_stack && callchain_param.enabled)
> > +		symbol_conf.show_branchflag_count = true;
> > +
> >   	sort__mode = SORT_MODE__TOP;
> >   	/* display thread wants entries to be collapsed in a different tree */
> >   	perf_hpp_list.need_collapse = 1;
> >